Fair Value (Schedule of Fair Value Measurements, Assets, Using Significant Unobservable Inputs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	$ 6,894	$ 6,931	$ 6,980	$ 8,691
Transfers into Level 3, Assets	15	21	154	136
Transfers out of Level 3, Assets	(297)	(993)	(796)	(5,210)
Recorded in Revenue, Assets	(7)	112	165	270
Recorded in Other Comprehensive Income, Assets	(15)	25	25	37
Purchases, Assets	1,163	1,032	2,392	4,015
Issuances, Assets	0	0	0	0
Sales, Assets	(24)	(45)	(59)	(118)
Settlements, Assets	(349)	(565)	(1,481)	(1,303)
Fair Value, ending balance, Assets	7,380	6,518	7,380	6,518
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	(16)	(47)	29	(71)
Derivative instruments, assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets				178
Transfers into Level 3, Assets				0
Transfers out of Level 3, Assets				0
Recorded in Revenue, Assets				(137)
Recorded in Other Comprehensive Income, Assets				0
Purchases, Assets				162
Sales, Assets				0
Settlements, Assets				(104)
Fair Value, ending balance, Assets		99		99
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End				(71)
Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	121	160	113	168
Transfers into Level 3, Assets	0	0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Recorded in Revenue, Assets	(21)	(69)	119	(127)
Recorded in Other Comprehensive Income, Assets	0	0	0	0
Purchases, Assets	7	75	25	162
Sales, Assets	0	0	0	0
Settlements, Assets	(30)	(67)	(180)	(104)
Fair Value, ending balance, Assets	77	99	77	99
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	(16)	(47)	29	(71)
Interest-rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets				10
Transfers into Level 3, Assets				0
Transfers out of Level 3, Assets				0
Recorded in Revenue, Assets				(10)
Recorded in Other Comprehensive Income, Assets				0
Purchases, Assets				0
Sales, Assets				0
Settlements, Assets				0
Fair Value, ending balance, Assets		0		0
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End				0
Categories of investments, marketable securities, available-for-sale securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	6,773	6,771	6,867	8,513
Transfers into Level 3, Assets	15	21	154	136
Transfers out of Level 3, Assets	(297)	(993)	(796)	(5,210)
Recorded in Revenue, Assets	14	181	46	407
Recorded in Other Comprehensive Income, Assets	(15)	25	25	37
Purchases, Assets	1,156	957	2,367	3,853
Sales, Assets	(24)	(45)	(59)	(118)
Settlements, Assets	(319)	(498)	(1,301)	(1,199)
Fair Value, ending balance, Assets	7,303	6,419	7,303	6,419
Categories of investments, marketable securities, available-for-sale securities | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	864	933	825	1,189
Transfers into Level 3, Assets				50
Transfers out of Level 3, Assets	(93)		(92)	(251)
Recorded in Revenue, Assets
Recorded in Other Comprehensive Income, Assets	(1)	3	(1)	3
Purchases, Assets			92
Issuances, Assets
Sales, Assets
Settlements, Assets	(29)	(30)	(83)	(85)
Fair Value, ending balance, Assets	741	906	741	906
Categories of investments, marketable securities, available-for-sale securities | Total asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	4,252	3,852	4,649	3,749
Transfers into Level 3, Assets		12		33
Transfers out of Level 3, Assets	0	(47)	(175)	(388)
Recorded in Revenue, Assets	13	12	41	37
Recorded in Other Comprehensive Income, Assets	(7)	18	31	29
Purchases, Assets	793	608	1,358	1,401
Sales, Assets	(24)		(59)	(73)
Settlements, Assets	(285)	(279)	(1,103)	(612)
Fair Value, ending balance, Assets	4,742	4,176	4,742	4,176
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, student loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	380	484	588	860
Transfers into Level 3, Assets				0
Transfers out of Level 3, Assets	0		(175)	(341)
Recorded in Revenue, Assets		1	1	2
Recorded in Other Comprehensive Income, Assets	(2)	5	6	(5)
Purchases, Assets			0
Sales, Assets			(26)
Settlements, Assets	(10)	(12)	(26)	(38)
Fair Value, ending balance, Assets	368	478	368	478
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, credit cards
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	24	274	67	91
Transfers into Level 3, Assets				21
Transfers out of Level 3, Assets	0	(36)	0	(36)
Recorded in Revenue, Assets		1	0	4
Recorded in Other Comprehensive Income, Assets	0	(1)	0	(5)
Purchases, Assets			0	224
Sales, Assets			0	(61)
Settlements, Assets	0	0	(43)	0
Fair Value, ending balance, Assets	24	238	24	238
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	3,848	3,094	3,994	2,798
Transfers into Level 3, Assets		12		12
Transfers out of Level 3, Assets	0	(11)	0	(11)
Recorded in Revenue, Assets	13	10	40	31
Recorded in Other Comprehensive Income, Assets	(5)	14	25	39
Purchases, Assets	793	608	1,358	1,177
Sales, Assets	(24)		(33)	(12)
Settlements, Assets	(275)	(267)	(1,034)	(574)
Fair Value, ending balance, Assets	4,350	3,460	4,350	3,460
Categories of investments, marketable securities, available-for-sale securities | Total non-U.S. debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	1,365	1,636	1,219	3,296
Transfers into Level 3, Assets		0	139	0
Transfers out of Level 3, Assets	(104)	(823)	(429)	(4,257)
Recorded in Revenue, Assets	1	1	4	1
Recorded in Other Comprehensive Income, Assets	(1)	4	1	4
Purchases, Assets	313	349	727	2,169
Sales, Assets	0		0	0
Settlements, Assets	6	(11)	(81)	(57)
Fair Value, ending balance, Assets	1,580	1,156	1,580	1,156
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	328	273	555	1,457
Transfers into Level 3, Assets				0
Transfers out of Level 3, Assets	0	(147)	(208)	(1,642)
Recorded in Revenue, Assets	0		0	0
Recorded in Other Comprehensive Income, Assets	(1)	0	(1)	3
Purchases, Assets	0	156	0	463
Sales, Assets	0		0	0
Settlements, Assets	13	3	(6)	4
Fair Value, ending balance, Assets	340	285	340	285
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	756	1,362	524	1,768
Transfers into Level 3, Assets			139	0
Transfers out of Level 3, Assets	(104)	(676)	(181)	(2,243)
Recorded in Revenue, Assets	1	1	4	1
Recorded in Other Comprehensive Income, Assets	1	4	2	4
Purchases, Assets	164	0	399	1,206
Sales, Assets	0		0	0
Settlements, Assets	(19)	(14)	(88)	(59)
Fair Value, ending balance, Assets	799	677	799	677
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	281	1	140	71
Transfers into Level 3, Assets			0	0
Transfers out of Level 3, Assets	0	0	(40)	(372)
Recorded in Revenue, Assets	0		0	0
Recorded in Other Comprehensive Income, Assets	(1)	0	0	(3)
Purchases, Assets	149	193	328	500
Sales, Assets	0		0	0
Settlements, Assets	12	0	13	(2)
Fair Value, ending balance, Assets	441	194	441	194
Categories of investments, marketable securities, available-for-sale securities | State and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	45	49	48	50
Transfers into Level 3, Assets		0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Recorded in Revenue, Assets	0	0	0	0
Recorded in Other Comprehensive Income, Assets	(1)	(1)	(1)	0
Purchases, Assets	0	0	0	0
Sales, Assets			0
Settlements, Assets	0	0	(3)	(2)
Fair Value, ending balance, Assets	44	48	44	48
Categories of investments, marketable securities, available-for-sale securities | Collateralized mortgage obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	238	301	117	227
Transfers into Level 3, Assets	15	0	15	44
Transfers out of Level 3, Assets	(100)	(123)	(100)	(314)
Recorded in Revenue, Assets	0	168	1	369
Recorded in Other Comprehensive Income, Assets	(5)	1	(5)	1
Purchases, Assets	50	0	190	283
Sales, Assets	0	(45)	0	(45)
Settlements, Assets	(11)	(178)	(31)	(441)
Fair Value, ending balance, Assets	187	124	187	124
Categories of investments, marketable securities, available-for-sale securities | Other U.S.debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	9	0	9	2
Transfers into Level 3, Assets	0	9	0	9
Transfers out of Level 3, Assets	0	0	0	0
Recorded in Revenue, Assets	0	0	0	0
Recorded in Other Comprehensive Income, Assets	0	0	0	0
Purchases, Assets	0	0	0	0
Sales, Assets	0	0	0	0
Settlements, Assets	0	0	0	(2)
Fair Value, ending balance, Assets	$ 9	$ 9	$ 9	$ 9